1. Field of the Invention
This invention relates to a side-looking or monitoring apparatus for a motor vehicle which can monitor an object such as a man or a vehicle which approaches from a side direction road when a driver""s own vehicle approaches an intersection or outgoes from a garage facing the road, thereby ascertaining safety.
2. Description of the Related Art
When the driver""s own vehicle approaches the intersection with bad visibility or outgoes from the garage facing a road, a driver stops the vehicle to ascertain left and right safety, and when he decides there is no approaching object, approaches the side direction road intersecting his own vehicle. However, the distant place of the side direction road is often out of hid sight as long as the vehicle does not approaches the side direction road to a certain degree. Therefore, the object such as another vehicle approaching from the far distance of the side direction road is out of his sight. In this case, there is a fear of a collision accident as a result that his own vehicle as-is approaches the side direction road without noticing the object.
In order to obviate such a fear, a side-monitoring apparatus for a motor vehicle as shown in FIG. 9 has been proposed in which images on both side directions of the vehicle picked up by cameras mounted toward both side directions are displayed on a display to assure the sight of the driver before the vehicle approaches the side direction road.
However, when the above side-monitoring apparatus is used, the driver must eye the display for safety ascertainment, and may miss the other vehicle displayed on the display. Further, when the driver only sees the display, it is difficult for him to decide whether or not the approaching object running on the side direction road may collide with his own vehicle.
Under the circumstance described above, an object of this invention is to provide a side-monitoring apparatus for a motor vehicle which can automatically decide the danger of collision with an object approaching from a side direction road using the image acquired by an image pick-up means mounted on the vehicle so that the present status of the side direction road can be known accurately.
In order to attain the above object, in accordance with this invention, as shown in FIG. 1, there is provided a side-monitoring apparatus for a motor vehicle comprising: image pick-up means 1 mounted in the motor vehicle for picking up an image of a side direction of the vehicle; approaching object detecting means 41a for detecting approaching degree of an approaching object which approaches a driver""s own vehicle from a side direction road crossing his own vehicle on the basis of two images picked up at two timings apart by a prescribed interval by the image pick-up means; and danger decision means 41b for deciding a danger on the basis of the approaching degree. In this configuration, using the images picked up by the image pick-up means mounted in the driver""s own vehicle, the danger of collision with the object approaching from the side direction road of his own vehicle can be automatically decided.
Preferably, the approaching object detecting means comprises movement quantity extracting means 41a1 for extracting a movement quantity having a component of a direction approaching the driver""s own vehicle from a movement quantity of the same object between the two images picked up by the image pick-up means, the extracted movement quantity representing the movement quantity of the approaching object, wherein the approaching degree is detected in terms of a location and magnitude of the movement quantity of the approaching object. In this configuration, using the images picked up by the image pick-up means installed at the driver""s own vehicle, the danger of collision with the object approaching from the side direction road of his own vehicle can be automatically decided.
Preferably, the approaching object extracting means extracts the movement quantity of the approaching object by detecting only the movement quantity of the same object having the component of the direction approaching the driver""s own vehicle and a component of the direction his own vehicle is running or to run. In this configuration, it is not necessary to detect the movement quantity of the same object in the direction opposite to the direction his own vehicle is running or to run, thereby realizing the necessary computation for a short time.
Preferably, the approaching object detecting means comprises movement quantity extracting means for extracting a movement quantity of the same object residing between the two images picked up by the image pick-up means and having a component of a direction the driver""s own vehicle is running or to run, the extracted movement quantity representing the movement quantity of the approaching object, wherein the approaching degree is detected in terms of a location and magnitude of the movement quantity of the approaching object. In this configuration, even when the image pick-up means is provided at a low position of the vehicle, the danger of collision with the object approaching his own vehicle can be automatically decided, thereby permitting the image pick-up means to be mounted at any height.
Preferably, the movement quantity extracting means extracts, as the movement quantity of the approaching object, the movement quantity of the same object residing between the two images picked up by the image pick-up means minus a changing degree corresponding to running of the driver""s own vehicle from the movement quantity of the approaching object. Therefore, even when the movement quantity of the same object is varied because the driver""s own vehicle has run slightly, the movement quantity of the object approaching when the driver""s vehicle approaches the side direction road can be detected accurately, thereby permitting danger of collision with the object approaching from the side direction road to be decided more accurately.
Preferably, the approaching object detecting means comprises: FOE detecting means 41a-2 for detecting an FOE (focus of extension) in each of the images at intervals of a prescribed time; and the movement quantity extracting means removes a movement quantity of the FOE between the two images as the changing degree. In this configuration, since the changing degree can be removed accurately, danger of collision with the object approaching from the side direction road can be decided more accurately.
Preferably, the approaching object detecting means comprises movement distance detecting means for detecting a distance the driver""s vehicle runs for a prescribed time; and the movement extracting means removes a value corresponding to the distance as the changing degree from the movement quantity of the same object. In this configuration, the changing degree can be removed easily.
Preferably, the movement quantity extracting means removes only the changing degree not smaller than a prescribed value. In this configuration, it is not required to remove the changing degree when it is smaller than the prescribed value, thereby realizing the necessary computation for a short time.
Preferably, the approaching object detecting means comprises: FOE detecting means 41a-2 for detecting an FOE (focus of extension) in each of the images picked up at intervals of a prescribed time; and movement quantity extracting means 41a-1 for extracting a movement quantity in a direction diverging from the FOE from a movement quantity of the same object between the two images picked up by the image pick-up means, the extracted movement quantity representing the movement quantity of the approaching object, wherein the approaching degree is detected in terms of a location or magnitude of the movement quantity of the approaching object. In this configuration, by only searching the same object in a single direction diverging from the FOE on the two images picked up at intervals of a prescribed time, the movement quantity of the approaching object can be extracted, thereby realizing the necessary computation for a short time.
The above and other objects and features of the invention will be more apparent from the following description taken in conjunction with the accompanying drawings.